1. Field of the Invention
This invention relates to a releasing agent applicator for use in, for example, a plain paper copying machine or a facsimile apparatus, and a method of applying releasing agent with the applicator.
2. Description of the Prior Art
Referring to FIG. 5, a fixing mechanism in a plain paper copying machine essentially comprises a hot fixing roller 1 and an electric pressing roller 13, such as a rubber roller. Paper 11 is passed between the rollers 1 and 13 and heated under pressure, whereby the toner 12 which has been transferred onto the paper 11 is fixed. It also includes a blade 14 and a peeling pawl 15.
When the paper is fed between the rollers, it is likely to stick to, and get wound on, the roller or rollers resulting in the failure of the toner to be properly fixed. It is also likely that the toner may adhere to the fixing roller and thereby cause the formation of a double image (the so-called offset phenomenon). It is, therefore, usual to apply a releasing agent to the fixing and pressing rollers. Silicone oil is usually used as the releasing agent.
A conventional device for applying a releasing agent to those rollers in a low-speed general-purpose copying machine comprises a heat resistant felt 3 impregnated with silicone oil and attached to a housing 2 formed from a heat resistant plastic or metal, as shown in FIG. 4. It is simple in construction and inexpensive. This device has, however, a number of drawbacks as will hereunder be pointed out.
(1) The toner which has been offset on the fixing roller clogs that surface of the felt which is brought into contact with the roller, and disables the felt to apply oil to the roller. The toner adhering to the felt damages the surface face of the fixing roller. Therefore, it is necessary to change the felt as often as each time about 10,000 sheets of paper have been printed.
(2) It is impossible to adjust the amcunt of oil which is applied to the roller.